PROJECT SUMMARY: Since the initial recognition of the Zika virus (ZIKV) outbreak in Brazil in 2015, 84 countries have reported evidence of autochthonous ZIKV transmission. ZIKV has emerged as one of the most challenging and concerning viral infections in this decade; principally due to its association with Congenital Zika Syndrome and Guillain-Barr Syndrome. An estimated 80% of cases of ZIKV infection are asymptomatic and symptomatic cases are of uncertain etiology as symptoms are shared with many other illnesses. Therefore, available clinical data are ineffective for community-level surveillance of ZIKV infection, highlighting the need for novel and innovative diagnostic tools in the fight against ZIKV. The primary objective of this research is to optimize a method for detection of ZIKV in sewage and to enhance understanding regarding the evolution and emergence of ZIKV in poor, urban communities. We propose to first the stability of ZIKV RNA in sewage, compare methods for detection and recovery of ZIKV RNA in sewage, and examine the association between ZIKV RNA in sewage samples and ZIKV prevalence in a cohort in Salvador, Brazil. The proposed study will clarify how detection of ZIKV in sewage can enable detection of community-level infection; allow for the use as a community diagnostic tool, and enable prompt public health action to protect the most vulnerable from the disease and its impacts.